Here is one way: use an intermediate variable z, and do it in two steps:
({1, 2, 3, 3, 1, 2} //. {{x___, 1, 2, y___} -> {x, z, y}}) //.
{{x___, z, y___} -> {x, Sequence[1, 2, 3], y}}
Ingolf Dahl
ingolf.dahl at telia.com
Sweden
-----Original Message-----
From: Erich Neuwirth [mailto:erich.neuwirth at univie.ac.at]
To: mathgroup at smc.vnet.net
Subject: [mg54250] rules and lists
I would like to replace sublists of a list to be replaced by another
list, such that for example the rule
{1,2}->{1,2,3}
wout tranform
{1,2,3,3,1,2} into
{1,2,3,3,3,1,2,3}
Simply gibbin the transformation rule in the form
{x___,1,2,y___}->{x,1,2,3,y}
does not work.
What is the idiom to do what I want?